Various devices are available for purifying the air in a room. One type of room air purifier that is widely known and used is an electrostatic air cleaner. Electrostatic air cleaners use electric energy to generate electrostatic forces which create air flow without the use of a fan or other moving parts. Electrostatic forces also enable the air cleaner to collect airborne contaminants such as dust, smoke, oil mist, pollen, pet dander and other small debris particles from the air circulated in dwellings, workplaces, and other structures.
Generally, known electrostatic air cleaners utilize two arrays of electrodes excited by high-voltage. In a known design, the first electrode array comprises wire or rod-shaped electrodes (hereinafter “wire electrodes”), while the second electrode array comprises plate electrodes. A high-voltage generator creates an electrical charge between the first and second electrode arrays.
The particulate matter enters the region of the first electrode array and is charged before entering the region of the second electrode array, where it is removed from the air stream. Specifically, due to the high-voltage charge at the wire electrodes, free electrons are stripped off of atoms and molecules in the surrounding air. These electrons migrate to the positively charged wire electrodes, where they are collected. The removal of free electrons leaves the stripped atoms and molecules positively charged, which are repelled from the positively charged wire electrodes and attracted to the negatively charged plate electrodes. The addition of the electrons from the negatively charged plate electrodes also produces negative air ions that are propelled from the trailing edge of the plate electrodes. Thus, the ionic forces exerted on atoms and molecules create a silent movement of air through the air cleaner.
It is also known to incorporate an ultraviolet lamp in the airflow of an electrostatic air cleaner to create a germicidal air cleaner. However, there are several deficiencies in the known designs of germicidal air cleaners. For example, the placement of the ultraviolet lamp in the electrostatic air flow interferes with the substantially linear electrostatic air flow from the air inlet to the air outlet, thus lowering the effectiveness of the electrostatic function of the air purifier. Furthermore, the germicidal lamp is most effective if the air flows in a longitudinal direction to the lamp because of the increased dwell time near the lamp. However, in known designs, the germicidal lamp is positioned such that the air flows transversely with respect to the lamp, thus lowering the germicidal effectiveness of the air purifier.
Accordingly, it is desirable to provide an air cleaner that has electrostatic and germicidal functions, wherein the air flows at a high rate with relatively low noise, and wherein the components are positioned such that the individual parts are easily accessible for cleaning and maintenance.